Latch needle having an improved trapping space

Abstract

A latch needle includes a shank; a hook formed at an end of the shank and having a hook tip; and a latch pivotally supported by the shank and cooperating with the hook. The latch has a closed state and a reverse state. In the closed state the hook and the latch together define a closed trapping space and in the reverse state the hook defines an open trapping space constituted essentially by an inner hook space. The latch includes an inner contour facing the trapping space in the closed state, a free end lying on the hook in the closed state and a stepped portion formed on the inner latch contour and adjoining the free latch end.

What is claimed is:  
     
       1. A latch needle comprising 
       (a) a shank;  
       (b) a hook formed at an end of said shank and having a hook tip; and  
       (c) a latch pivotally supported by said shank and cooperating with said hook; said latch having a closed state and a reverse state; in said closed state said hook and said latch together defining a closed trapping space and in said reverse state said hook defining an open trapping space comprising an inner hook space; said latch including  
       (1) a free end lying on said hook in said closed state; and  
       (2) an inner contour facing said trapping space in said closed state; said inner contour having a first length portion and an adjoining second length portion; said second length portion being formed by a projection terminating a stepped portion; said projection being situated between said free end and said first length portion; said first length portion having a smooth and gradual transition into said second length portion; said stepped portion being located between said free end of said latch and said transition and facing said free end; said projection being in a non-overlapping relationship with said hook in said closed state of said latch; said projection jutting beyond said first length portion and shielding said hook tip in said closed state of said latch for deflecting a thread away from said hook tip.  
     
     
       2. The latch needle as defined in  claim 1 , further comprising a needle back; further wherein said hook tip has a curved contour merging into an inner contour of said hook at a first location; said stepped portion merging into said inner contour of said latch at a second location situated at a height such that, in said closed state, an imaginary straight line interconnecting said first and second locations extends parallel to said needle back. 
     
     
       3. The latch needle as defined in  claim 1 , further comprising a needle back; further wherein said projection jutting into said trapping space in said closed state of said latch; and further wherein said hook tip has a curved contour merging into an inner contour of said hook at a first location; said stepped portion merging into said inner contour of said latch at a second location situated at a height such that an imaginary straight line interconnecting said first and second locations forms an acute angle with said needle back. 
     
     
       4. The latch needle as defined in  claim 1 , wherein in said closed state of said latch a gap is defined by said hook and said stepped portion; said gap being narrower than an expected minimum diameter of a thread processed by said latch needle. 
     
     
       5. The latch needle as defined in  claim 1 , wherein said latch has a width dimension measured perpendicularly to a pivotal plane of said latch; said width dimension decreasing toward a terminus of said free end. 
     
     
       6. The latch needle as defined in  claim 1 , wherein said latch has a groove for receiving a portion of said hook in the closed state of said latch; further wherein said free end has an engagement face cooperating with said groove and an imaginary prolongation of said engagement face forms a line; said stepped portion being situated between said trapping space and said line. 
     
     
       7. The latch needle as defined in  claim 1 , wherein said latch has rounded lateral edges at said inner contour. 
     
     
       8. The latch needle as defined in  claim 1 , wherein said latch has a height dimension measured parallel to a pivotal plane of said latch; said height dimension decreasing toward a terminus of said free end. 
     
     
       9. The latch needle as defined in  claim 1 , wherein said hook has a groove receiving said free end of said latch in said closed state thereof; further wherein said free end has an engagement face cooperating with said groove and an imaginary prolongation of said engagement face forms a line; said stepped portion being situated between said trapping space and said line. 
     
     
       10. The latch needle as defined in  claim 9 , wherein said groove of said hook has a greatest depth which, is less than one half of the thickness of the hook. 
     
     
       11. The latch needle as defined in  claim 9 , wherein said groove of said hook has a greatest depth which, is approximately one third of the thickness of the hook.